Method and means for treating fibrous material with electric current



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` XY y EK j f D K I f Sept. 4, 1,934. C A. UHLMANN Er AL 1,972,608

METHCD AND MEANSLECR TEEATINE FIERoUs MATERIAL WITH ELECTRIC CURRENT Filei Jan. '7, 19:51

Patented Sept. 4, 1:9434

METHOD AND MEANS FOR TREATIN G FIBROUS MATERIAL WITH ELECTRIC CURRENT Alfred Uhlmann, Berlin-Lichterfelde, Fritz Seidel, Berlin-Copenick, and Julian Ronke, Langenbielau, Germany, assignors to firm: Christian Dierig Aktiengesellschaft, Berlin-Grunau, Germany Application January 7' 1931, serial No. 507,068 In Germany .lanuary 10, 1930 Claims. (Cl. 204-1) This invention relates, broadly speaking, to a method for treating fibrous material for textile purposes and to means for carrying out this new method. It is particularly concerned with a method and with means for treating such iibrous materials with alternating electric current.

Various methods are known for treating fibrous material which contain the step of causing a continuous or direct electric current to act on the material during the refinement of this material. Electric current of this kind has been, for instance, frequently applied for bleaching yarn or fabrics. The action of the direct electric current is based on the well known electrolysis reactions.

We have found that the bleaching, washing, dressing and other steps of refinement of fibrous material can be considerably improved by applying to the fibrous material an alternating electric current. When alternating electric current is applied to the fibrous material during bleaching and other steps of refinement, a considerable decrease in duration of the Various steps is reached.

It is an object of the present invention to rev ine fibrous materials for textile purposes by the influence of alternating electric currents of high or medium frequency.

It is a further object of the invention to subject librous materials to the action of a high or medium frequency current, while they are positioned between opposite, electrodes connected to the alternating current supply.

It is a further object of the invention to moisten fibrous material with suitable bleaching liquors and then to lead a high or medium frequency current through the electric material.

A further object of the invention consists in a device for refining fabric containing two series of rollers each of the series being connected to a different pole of the alternating circuit.

Other objects of the new method and the new means for carrying out the method will be clearer understood by the following detailed description, partly with reference to the appended drawing. It should be pointed out, however, that the device shown in the appended drawing is only described by way of an example and that the invention should not be limited to the specic details of this example neither for the part of this invention which is concerned with the method nor for the part relating to the means for carrying out the new method, as many modifications will easily present themselves to anybody skilled in the art.

For giving distinct definitions it should be mentioned that the term high and medium frequency used in this specification and in the claims comprises frequencies of 500 cycles per second up to billions of cycles. The higher range of cycles may extend to two billions of cycles per second and more. Electric`"currents"having'such frequencies do not electrolyze the substances which are employed.

In carrying out the new method an alternatlng electric current is led through the iibrous material which is positioned between electrodes connected to opposite poles of the alternating current supply. To ensure the passage of the electric current through the brous material, this material must contain moisture. In most cases it is necessary, therefore, to moisten the fibrous 4material previous to the electrical treatment. This moistening can be supplemented by an additional moistening during the electric treatment, as will be described in detail in a later part of the invention. y

The hitherto known electric treatment with continuous current has been in most cases carried out in the way that the fibrous material was subjected to the action of the direct electric current in a bath of liquid. It is an important feature of the present invention that the new method is carried out outside of a bath. It is apparent that the treating of the material outside of a bath results in considerable savings of chemicals.

Referring now to the drawing Fig. 1 is a diagrammatic view of a machine according to the invention and shows in particular the passage of the fibrous material through the machine. Fig. 2 is a diagrammatic View of the electric connections.

The machine shown in Fig. 1 is particularly designed for the treatment of fabrics. The machine comprises two sets of rollers, the outer set consisting vof a plurality of rollers 1 connected to one terminal of an alternating current supply (not shown), the inner Set consisting of a plurality of rollers 2 connected to the other terminal of an oscillator. A container 3 with guiding rollers 4 and 5 is filled with a suitable liquid. The fabric 6 enters the device over guiding roller 7 and passes between the rollers 1 and 2 of the inner and of the outer set.

As a rule, the machine will be run with a plurality of layersv of fabric between the two sets of rollers. Attention must be taken to ensure that the space between the rollers 1 and 2 is filled by the fabric, as it is necessary that one surface of the layer or of the bundle of layers always lll) contacts with the one set of rollers and that the other surface contacts with the other set.

It has to be understood that adjacent layers of fabric are in full contact with each other, if a plurality or a bundle of layers passes between the rollers.

From Fig. 2 it is apparent that each of the rollers 2 of the inner set is connected over a common line 10, 11 to terminal 14 of an oscillator 16, while the rollers 1 of the outer set are connected to the other terminal 15 of oscillator 16 by branches 12 and 13. The rollers 1 and 2 are made of metal.

Rollers 4, 5 and 7 are guiding rollers only and are not connected to the electric current. The guiding rollers preferably are made of nonconductive material. Before passing into the machine the fabric had been moistened with a suitable liquid. The composition of the liquid depends upon the properties of the fabric and also upon the treatment which has to be performed. As the art of bleaching, scouring, coloring and other steps of refinement or finishing of fibrous material is very highly developed and as a very great number of suitable compositions of chemical solutions are known in the art for all these and other different steps in question, a detailed description of different compositions of v solutions is deemed unnecessary, and only one example of composition is given in the following.

' One part of a solution containing 4% by weight of sodium carbonate and 3% by weight of sodium peroxide is added to 14 parts of water, to which is added 0.5 g. per liter of a suitable wetting agent.

After having passed the first part of the machine a supplementary moistening with the same solution is performed by leading the material through the container 3. The fabric passes then between the second part of the two sets of rollers. This cycle can be carried out several times.

The fabric 6 is fed out of the device at 9 and is led over rod 8. Rod 8 is arranged at an angle of preferably relative to the axes of rollers 1 or 2. By leading fabric 6 over this rod the fabric passes out of the machine at right angles to the direction of its entrance. While the plurality of layers of fabric 6 pass between the sets of rollers 1 and 2, the alternating high frequency or medium frequency current passes through the layers in a direction substantially at right angles to the direction of movement of the fabric. The electric current causes a very considerable acceleration of the bleaching and other reaction.

It has been found that complete refinement of raw cotton fabric can be reached, for instance, if the fibrous material, which had been previously moistened with the above described solution is treated a rst time for about 10 minutes with alternating high frequency current. Then the material is subjected to an intermediate washing treatment comprising washing, steeping in a solution of dilute acid, and again washing.

The fibrous material is then moistened with the chemical solution for a second time and is subjected to the action of the high frequency current for about 20 minutes. Then follows an intermediate washing treatment of the previously mentioned kind, and eventually a third moistening, electric-treatment of about 5 minutes and final washing. It is well known in the bleaching and scouring of fabrics, and the removal of size therefrom, to use different liquids in these respective steps.

The frequency of the alternating current may be 500 cycles per second for al1 of the three stages of the previously described process or it may, according to practical experience, be found more advantageous to increase or decrease the frequency between the different stages within the limits formerly mentioned.

By this process the sizing contained in the fabric and yarn is decomposed, the material is scoured, the fatty compounds are removed and the fibrous material is completely bleached. These effects were hitherto reached by a sequence of treatments which took about 48 hours. By the new method and means similar results can be reached in less than one hour.

The process of removing the sizing consists mainly in decomposing the starch into glucose, which forms the main part of the sizing. This reaction takes place under the oxidizing action of the sodium peroxide. The glucose which is readily soluble in water is then removed by washmg.

The scouring or removing of the fatty compounds from the brous material is secured by saponiiication of these compounds under action of the spdium peroxide and sodium carbonate.

The blecliWN ""librous'inat'erial is reached by the action of the oxygen which is set free from the sodium-peroxide. The bleaching therefor is not primarily the result of an electrolytic action, as is the aim of allwtrgamtmgentswithirectgurrentmpf-rlymhgmhical one, the alternating current sing apparently only a loosening of the molecules of the bleachingagents. It has been found only lately thatv alternating current of various frequencies may be used to good advantage for this purpose. In this process the sodium carbonateacts as a means for decreasing the speed of the bleaching action. This is necessary since the fact that too quick bleaching might weaken the strength of the fibres.

In the above described example the first electrical treatment will effect nearly complete decomposition of the sizing. Also part of the scouring will be effected by this step of treatment, as well as a slight bleaching.

The second electrical treatment will in the first instance act as a bleaching medium. At the same time the scouring is completed. The third short electrical treatment serves for rening the fabric and substantially consists in an additional bleaching reaction.

Speaking generally, it might be said that it has been found that voltages of various ranges will give satisfactory results, and that also a great range of frequencies is suitable for the new process. Frequency and voltage should be varied in each case until the best results are secured for the particular fibrous substance and the particular liquid.

It should be mentioned that various modifications of the described device can be used with equally good result. For instance, instead of the rollers 1 and 2 one or more pairs of oppositely located plates may be used as contact members. The plates may be perforated to allow moistening of the fibrous material during the application of the high or medium frequency current.

The alternating high and medium frequency current can be used for refining fibrous textile material of all kind such as vegetable fibres, animal bres or artificial bres, for instance artificial silk. It is appliable to the fibrous material in any state of manufacture. Loose libre, yarn and fabrics can be treated in the described way. The fibrous material, containing a liquid which is adapted to react with said ibrous material,

may be nrst subjected to the action of a high frequency current, and said material may then be subjected to the action of an alternating current of lower frequency.

While as a rule it will be necessary to articially moisten the fibrous material before it is subjected to the electrical treatment, it is possible to leave out the step of moistening in some cases, i. e. where the fibres themselves contain already enough moisture for giving them a sufcient degree of electrical conductivity for carrying out the alternating current treatment.

As hereinbefore stated, the new treatment results in a very considerable decrease of duration of the different renement steps. It is further made possible to perform the Whole treatment as a continuous process.

Having shown and described the invention in its aspects and details, what is claimed is particularly pointed out in the following claims.

I claim:

1. A method of treating brous material which consists in subjecting the material to the action of an alternating current while said material is moistened with a liquid which is adapted to chemically react with said material under the action of said current, the frequellCy vr,Ofmsaid alternating current being suiicietly high tv electrolysis,... ""2"A"rethod of treating textile material which contains a liquid adapted to chemically react with the same under the action of an electric current, which consists in subjecting a plurality of layers of said material to the action of an alternating current whose frequency is suiciently high to prevent any substantial electrolysis of said liquid, while causing the two non-adjacent faces of said layers of material to directly receive said current.

3. A method of treating textile material which contains a liquid adapted to chemically react with the same under the action of an electric current, which comprises the step of subjecting the material to the actionof an alternating current while said material passes and is continuously moved between two series of oppositely arranged electrodes, the frequency of said current being sufficiently high to prevent any substantial electrolysis of said liquid.

4. A method of treating textile material which contains a liquid adapted to chemically react with the same under the action of an electric current which consists in causing layers of said material to contact with electrodes, said electrodes having said layers of material between them, and supplying an alternating current to said electrodes, the frequency of said current being sumciently high to prevent any substantial electrolysis of said liquid.

5. A method of treating a textile material which contains a liquid adapted to react with the same, which consists in first subjecting said material to the action of a high frequency electric current and then subjecting said material to the action of an alternating current of lower frequency.

6. A method of treating textile material which contains a liquid adapted to react with the same, which consists in feeding a layer of said material in contact with electrodes, in continuously moving said layer between and along said electrodes, in then remoistening said layers with a liquid adapted to react with said material; in then again feeding said material in contact with electrodes; and in supplying an alternating current to said electrodes.

7. A method of treating textile material which contains a liquid adapted to react with the same, which consists in subjecting said material to the action of a high frequency alternating current, then treating said material with a liquid or liquids adapted to assist in the desired reaction, subjecting the material again to the action of a high frequency alternating current, then treating said material again with a liquid or liquids adapted to cause said reaction, and then subjecting said material to the action of a high frequency current.

8. For use in treating textile material which is moistened with a liquid which can chemically react with said material under the influence of an electric current, electrodes adapted to contact with said material and a source of alternating current connected to said electrodes, the frequency of said alternating current being sufliciently high to prevent any substantial electrolysis of said liquid.

9. For use in treating a textile material which is moistened with a liquid which can chemically react with said material under the influence of an electric current, a plurality of spaced series of electrodes which are adapted to hold a plurality of layers of said material between them, and a source of alternating current to which said electrodes are connected, the members of said series being respectively connected to one of the terminals of said source, the frequency of said alternating current being suiiciently high to prevent any substantial electrolysis of said liquid.

10. For use in treating textile material, a tank adapted to contain a liquid which is adapted to chemically react with said material under the action of an electric current, electrodes located above said tank, said electrodes being connected to the terminals of a source of alternating current, and means adapted to lead a layer or layers of said material into and out of said tank and in contacting relationship with said electrodes, the frequency of said alternating current being sufciently high to prevent any substantial electrolysis of said liquid.

11. An apparatus for treating textile material comprising two spaced series of rollers which are adapted to hold and guide between them a layer or layers of said material; a source of alternating current, the terminals of which are respectively connected to the members of each series; a tank; and guide rollers being adapted to guide a layer or layers of said material through the tank.

12. A method of treating textile material which consists in leading through the material an alternating current, said material containing a liquid which is adapted to chemically react With said material under the action of an electric current, the frequency of said alternating current being sufficiently high to prevent any substantial electrolysis of said liquid.

13. A method of treating textile material which 135 consists in leading through the material an alternating current, while said material is moistened with a liquid which is adapted to chemically react with said material under the action of an electric current, the frequency of said alternating current being suiiiciently high to prevent any substantial electrolysis of said liquid.

14. A method of treating textile material which consists in leading outside of a liquid bath and through said material an alternating current, said material containing a liquid which is adapted to chemically react with said material under the action of an electric current, the frequency of said alternating current being suciently high 150 Tsi of remoistening said material, the frequency of y nating current through said material; the step said current being sufficiently bighigmlgevent electrolysis 4ojfmgaic-lv liquid and the repetitiomrfifv said two steps.

.s ALFRED UHLMANN.

` FRITZ SEIDEL.

JULIAN RONKE. 

